My RC24 resurrection

I just installed this one on my VF1000F ... work great.
https://www.ebay.com/itm/393682256707

 

Awesome! Thanks!


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Nice score 6. I would vote to replace.

 

Ok, I’ve swapped over HT leads and plugs from different cylinders and still no joy getting number 4 to light up.

So I’ve ordered cylinder head gaskets which will arrive next week, so I’ll get them off and check valve clearances and see it there’s anything going on with a stuck valve and As I’ve got to take the carbs off anyway, I’ll open up number 4 again and see if there’s anything I’ve missed or got wrong with the float and float needle.


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Could it be a coil? Just shootin out ideas before a tear down. never mind it sounds like you did that. duh....i dum.

 

I buy used genuine Japanese Mitsubishi pumps off of the newest, lowest mile bikes I can find on ebay. They are straight outlets, but I just use some 90 degree adapters. I get ~$150 pumps for about $25, usually along with some nice formed fuel line for other projects. They have the same vent and power plug style too.

That MTM pump sure looks decent, but I'm a little skeptical of where it is actually manufactured. I think the claim is Germany. A brand new German made fuel pump for $50? But I guess if it works and lasts, who cares?

 

Yeah, I’ve now ruled out everything spark-wise. So must be fuel. Hopefully not compression. AFAIK, it was deffo running on 4 cylinders when it went into storage, so either I need to look at my work in that carb or a gummy valve. Hopefully will have it sorted soon.

Btw, I really like the card gauge to look at float heights. Will make myself one when I check the float in carb 4.


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Before you go pulling the engine apart have you done a compression test …like squirrelman suggested?

 

Not yet, but I am intending to do one. Valve clearances need doing anyway. Definitely sounds ‘tappy’.


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Video of the number 4 carb. Some deposits on the bottom of the butterfly valve. What might that be telling me.

https://youtube.com/shorts/cdzgWP9XoFs?feature=share

Off to check float height again.


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So float too high?




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Remove all jets, valves etc. from the carb, inject fuel or brake cleaner in the holes and use compressed air to clean everything. Take care of the air jets at the air cleaner side, they were clogged sometimes and cause malfunction.
And organize a compressin tester...

 

And that is just touching the pin, not compressing the float bowl? doesn't seem insane, but the usual suspects would know exactly what kind of carb reaction that would cause.

 

Adjusted




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If up is up in that picture you are doing it wrong as stated earlier. But yes, it is "high" (in the first pic) it will probably be worse when checked properly.

You have to be holding / rotating the carbs in a way that the float is JUST contacting the valve and NOT depressing the the little spring loaded button in the valve. The weight of the float will usually depress the button some.

The floats need to be almost "hanging" and then rotate the carbs slightly to make contact.

 

Yes, fuel height is too high, so fuel level too low. For correct measure the carb should held perpendicular, then lean it carefully till the valve closes. With a single carb use a tube and blow inside till you feel the resistance of the fuel valve. At this point check the float height.

 

Post #136

 

Ok everyone. Thanks for your input. Carbs are off the bike still and won’t go back on for a while so I’ll regroup and have another look in a couple of days, while I wait for the cylinder head gaskets to arrive.


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to me it seems totally daft to go and replace the head gasket (ALOT could go wrong !) to fix your problem. only if you measure low compression would it justify head gasket work, and even then no guarantee of a fix.

have you tried a sprits of starting fluid sprayed into the #4 intake tract just to see if you get it firing briefly ?

if the float needle is leaking you'll see liquid fuel bubbling up from the main jet tube under the slide needle (with engine running), and the plug will be wet and shiny. since you have carbs apart, i'd suggest swapping float, needle and seat from a cylinder that's working to the bad one.

i had problem years ago with one '86 vfr cylinder not firing, turned out to be a bad circuit in the black box. i had always believed incorrectly that if the box failed there would be no sparks to all cylinders, not so !

 

Thanks Squirrelman. Quite a few folks have said that I should check and adjust valve clearances which would mean doing this anyway, wouldn’t it? There’s a definite ‘tap’ owing from somewhere and I’d have thought this should be done. However, always happy to try to do as little as possible!

so you’re saying the spark unit could be faulty? That sounds potentially, very expensive! They must be difficult to get hold of?

Anyway, will do my float height check properly, this evening, and check all the jets again. I’m getting really good at taking the carbs on and off!